Antiperspirant gel-solid stick composition containing a modified silicone carrier

ABSTRACT

Disclosed are anhydrous antiperspirant gel-solid sticks which comprise particulate antiperspirant active; a solid non-polymeric gellant that is substantially free of dibenzylidene alditol, inorganic thickening agents, organic polymeric gellants, n-acyl amino acid derivatives, or combinations thereof; an anhydrous liquid carrier containing polyalkylsiloxanes, polyalkyarylsiloxanes, polyestersiloxanes, polyethersiloxane copolymers, polyfluorosiloxanes, polyaminosiloxanes, or combinations thereof. The composition has a visible residue index of from about 11 to about 30 L-value, a product hardness of from about 500 to about 5,000 gramxforce, a rheology profile defined by a ratio of an elastic modulus (G&#39;) to a viscous modulus (G&#39;&#39;) of from about 0.1 to about 100. The refractive indices of the particulate antiperspirant active, the solid non-polymeric gellant, and the anhydrous liquid carrier are not matched. The compositions preferably comprise crystalline gellant particles having an average particle size of less than about 1  mu m and/or a particle morphology having an aspect ratio of greater than about 2. These compositions provide improved low residue performance, efficacy and aesthetics.

TECHNICAL FIELD

The present invention relates to antiperspirant compositions in the formof gel-solid sticks. In particular, the present invention relates toselect compositions in the form of gel-solid sticks that provideimproved low residue performance, efficacy and aesthetics, and whichcontain select modified silicone carriers.

BACKGROUND OF THE INVENTION

There are many types of topical antiperspirant products that arecommercially available or otherwise known in the antiperspirant art.Most of these products are formulated as aerosol or pump sprays, roll-onliquids, creams, emulsions, gels, gel-solids, or other solid stickformulations, and comprise an astringent material, e.g. zirconium oraluminum salts or combinations thereof, incorporated into a suitablecarrier. These products are designed to provide effective perspirationand odor control while also being cosmetically acceptable during andafter application onto the axillary area or other areas of the skin.

Within this product group, solid antiperspirant sticks have becomeespecially popular among consumers. These antiperspirant sticks comprisea solid matrix within which the antiperspirant active material iscontained. The active can be solubilized in a liquid carrier comprisingwater, glycols and/or other alcohols, or maintained within a solidmatrix as dispersed solids in an anhydrous system. The solid stickswhich contain dissolved active often provide some low residueperformance, but tend to be wet or sticky during and immediately afterapplication to the skin, and more importantly, are often not aseffective in providing antiperspirant and deodorant performance as solidsticks containing dispersed particulate active. Although theantiperspirant sticks which contain particulate actives are moreeffective, they also tend to leave a higher visible residue on the skin.

There have been many attempts at producing anhydrous antiperspirantsticks which contain dispersed particulate antiperspirant active, andwhich also provide improved efficacy and low residue performance duringand after application to the skin, or which otherwise provide productclarity prior to (as a packaged product) or after such application (as aclear or low-residue film on the skin).

One such attempt involves the combination of particulate antiperspirantactive, gellants and liquid carrier in a gel stick, wherein all suchcomponents in the combination have matching refractive indices.Refractive index matching allows for more passage of light through thegel stick with less scattering of the light, thus resulting in productswhich appear more clear or translucent as a packaged composition or wheninitially applied topically to the skin. These gel sticks, however, areexpensive to make due to the cost of using raw materials having onlyselect matching refractive indices. These compositions are also verydifficult to formulate given that refractive index matching for a threecomponent system (particulate active, solvent and gellant) is extremelydifficult, and greatly limits the materials that can be used to preparesuch a formulation.

Another attempt at making low residue antiperspirant sticks involves theuse of gellants such as dibenzylidene alditols. These gellants, however,like many other gellants known in the art, are not acid stable andtherefore tend to interact with the antiperspirant active due to theacidic nature of the active. This interaction can result in reducedefficacy of the active, poor gel formation, and lower gel stability overextended periods during shipping or storage. This interaction may alsocause processing difficulties at the temperatures and holding timesoften used during the formulation and manufacturing process. Thesegellants are also commonly used in combination with glycol carriers orother solvents which tend to be wet and sticky and irritating to theskin.

Yet another attempt at making low residue antiperspirant sticks involvesthe use of residue masking agents such as non-volatile paraffinichydrocarbon fluids, phenyl trimethicone, low melting point waxes andcombinations thereof. These agents are used in combination with stearylalcohol or other high residue waxes commonly used in solidantiperspirant sticks. These agents help reduce visible residue duringand immediately after application of the solid stick to the skin, butalso tend to be associated with an oily or sticky skin feeling duringapplication. Moreover, although the visible residue is reduced in suchcompositions, there remains a visible residue on the skin when used incombination with high residue waxes such as stearyl alcohol, and thisreduced residue is still more visible or apparent than the topicalresidue left by antiperspirant sticks which contain solubilizedantiperspirant active.

Other attempts at improving low residue performance from anantiperspirant composition has focused on the use of anhydrousantiperspirant creams. These creams can be applied to the skin byconventional means, or by a cream applicator device, and results in verylow residue during and immediately after application to the skin. Thesecompositions comprise particulate active dispersed throughout ananhydrous carrier, and either contained within a solid-like matrix orthickened with an inorganic or polymeric gellant or thickening agent.Many consumers, however, still prefer the convenience of using a solidantiperspirant stick, even if the solid stick tends to leave a highervisible residue on the skin.

A recent method of making low residue antiperspirant sticks is describedin U.S. Pat. No. 5,429,816, issued to Hofrichter et al. on Jul. 4, 1995,which description is hereby incorporated by reference herein. Theantiperspirant sticks provide low visible residue during and immediatelyafter application to the skin, and are physically and chemically stableover extended periods of time. The improved antiperspirant stickscomprise a dual gellant system having a primary gellant such as12-hydroxystearic acid or esters or amides thereof and a secondarygellant such as n-acyl amino acid derivatives. Formation of such anantiperspirant stick with such a dual gellant system has beencharacterized as a "gel-solid" antiperspirant stick.

An antiperspirant gel-solid, such as that described by Hofrichter et.al., is an antiperspirant stick having a three-dimensional,non-polymeric, gel network in which solvent is contained or trapped.These gel-solids are typically formed by solubilizing the gellant in thesolvent at temperatures above the melt point of the gellant and attemperatures at which the melted gellant is soluble in the solvent, andthen cooling the composition to form the desired gel-solid composition.The low residue gel-solids described by Hofrichter et al. are remarkablystable, both physically and chemically, and will maintain the desiredproduct hardness over an extended period of time. The gel-solidsdescribed by Hofrichter et al., however, are limited to select dualgellant systems and do not include or otherwise describe any method ofmaking a low-residue antiperspirant gel-solid stick containing any othergellant or gellant system.

It has now been found that other low-residue gel-solids can beformulated without reliance upon the select combination of gellantsdescribed by Hofrichter et al. The new low-residue gel-solids areanhydrous systems which comprise from about 0.5% to about 60% by weightof particulate antiperspirant active; from about 1% to about 15% byweight of a solid non-polymeric gellant that is substantially free ofdibenzylidene alditol, inorganic thickening agents, organic polymericthickening agents, n-acyl amino acid derivatives and combinationsthereof; from about 10% to about 80% by weight of an anhydrous liquidcarrier containing a modified silicone liquid carrier selected from thegroup consisting of polyalkylsiloxanes, polyalkyarylsiloxanes,polyestersiloxanes, polyethersiloxane copolymers, polyfluorosiloxanes,polyaminosiloxanes, and combinations thereof; wherein the compositionhas a visible residue index of from about 11 to about 30 L-value, aproduct hardness of from about 500 gram·force to about 5,000 gram·force,a ratio of an elastic modulus (G') to a viscous modulus (G") of fromabout 0.1 to about 100. The composition does not require refractiveindex matching of the particulate antiperspirant active, solidnon-polymeric gellant, and anhydrous liquid carrier to achieve lowresidue performance. The compositions preferably comprise gellantcrystalline particles having an average particle size of less than about1 μm, and/or an elongated particle morphology defined by an aspect ratioof greater than about 2.

It also has been found that the modified silicone carriers, whenincorporated into the antiperspirant gel-solid stick compositions asdefined herein, are effective in providing improved antiperspirant anddeodorant efficacy. These select modified silicone carriers areespecially effective when used in combination with other carrier liquidssuch as volatile silicones, and even more effective when used as aco-solvent for the solid non-polymeric gellant in place of other moretypical or conventional co-solvents such as polar, water-immiscible,co-solvents.

It is therefore an object of the present invention to provide ananhydrous antiperspirant gel-solid stick containing particulateantiperspirant active which provides improved low residue performance,efficacy and aesthetics, and further to provide such a compositionwithout reliance upon specific gellants such as dibenzylidene alditols,or dual gellant systems containing n-acyl amino acid derivatives. It isa further object of the present invention to provide such a compositionwithout reliance upon refractive index matching of component materials,or the use of solubilized antiperspirant active, to obtain productclarity or low residue performance. It is yet another object of thepresent invention to provide such a composition comprising an anhydrousliquid carrier containing select modified silicone carriers.

SUMMARY OF THE INVENTION

The present invention is directed to anhydrous antiperspirant gel-solidstick compositions which comprise from about 0.5% to about 60% by weightof particulate antiperspirant active; from about 1% to about 15% byweight of a solid non-polymeric gellant that is substantially free ofdibenzylidene alditol, inorganic thickening agents, organic polymericgellants, n-acyl amino acid derivatives, or combinations thereof; fromabout 10% to about 80% by weight of an anhydrous liquid carriercontaining a modified silicone liquid carrier selected from the groupconsisting of polyalkylsiloxanes, polyalkyarylsiloxanes,polyestersiloxanes, polyethersiloxane copolymers, polyfluorosiloxanes,polyaminosiloxanes, and combinations thereof; and wherein thecomposition has a visible residue index of from about 11 to about 30L-value, a product hardness of from about 500 gram·force to about 5,000gram·force, a rheology profile defined by a ratio of an elastic modulus(G') to a viscous modulus (G") of from about 0.1 to about 100. Therefractive indices of the particulate antiperspirant active, the solidnon-polymeric gellant, and the anhydrous liquid carrier are not matched.The compositions preferably comprise crystalline gellant particleshaving an average particle size of less than about 1 μm and/or aparticle morphology having an aspect ratio of greater than about 2. Thecompositions also preferably comprise from about 0.1% to about 50% byweight of the modified silicone liquid carrier, and more preferably incombination with a volatile silicone.

It has been found that the antiperspirant gel-solid stick compositionsof the present invention can provide low residue performance without theneed to use solubilized antiperspirant active, and without reliance uponselect low residue gellants such as dibenzylidene alditols or selectgellant combinations containing n-acyl amino acid derivatives. This isaccomplished by formulating an anhydrous gel-solid stick compositionhaving the select hardness and rheology profile preferably provided by anon-polymeric, three-dimensional crystalline gel network made up ofsmall, elongated crystalline particles having an average particle sizeof less than about 1 μm and/or a particle morphology defined by anaspect ratio of at least about 2.

It also has been found that the modified silicone carriers, whenincorporated into the antiperspirant gel-solid stick compositions asdefined herein, are effective in providing improved antiperspirant anddeodorant efficacy. These select modified silicone carriers areespecially effective when used in combination with other carrier liquidssuch as volatile silicones, and even more effective when used as aco-solvent for the solid non-polymeric gellant in place of other moretypical or conventional co-solvents such as polar, water-immiscible,co-solvents.

DETAILED DESCRIPTION OF THE INVENTION

The antiperspirant gel-solid stick compositions of the present inventionare anhydrous systems which are dispersions of particulateantiperspirant active held or contained within a non-polymericcrystalline gel-solid matrix.

The term "anhydrous" as used herein means that the antiperspirantgel-solid stick composition of the present invention, and the essentialor optional components thereof other than the particulate antiperspirantactive, are substantially free of added or free water. From aformulation standpoint, this means that the antiperspirant gel-solidstick compositions of the present invention preferably contain less thanabout 5%, preferably less than about 3%, more preferably less than about1%, most preferably zero percent, by weight of free or added water,other than the water of hydration typically associated with theparticulate antiperspirant active prior to formulation.

The term "low residue" as used herein refers generally to the visibleresidue left on the applied areas of the skin during or immediatelyafter application, and more specifically refers to the visible residueindex of the composition as defined by the methodology describedhereinafter.

The term "ambient conditions" as used herein refers to surroundingconditions under about one atmosphere of pressure, at about 50% relativehumidity, and at about 25° C., unless otherwise specified.

The term "substantially free" as used herein, unless otherwisespecified, refers to preferred negative limitations of the compositionsof the present invention, and are directed to the amount orconcentration of inorganic thickening agents, organic polymericthickening agents, dibenzylidene alditol gellants, n-acyl amino acidderivatives, or combinations thereof, in the composition. The term"substantially free" means that the compositions preferably contain lessthan an effective amount of such agents when used alone to provide anythickening or measurable viscosity increase to the composition. In thiscontext, the negative limitations pertain only to those thickening orgelling agents which are also solid under ambient conditions, and whichare not silicone containing materials or polymeric derivatives of12-hydroxystearic acid. Generally, the compositions preferably containless than 5%, preferably less than 2%, more preferably less than 1%,even more preferably less than 0.5%, most preferably zero percent, ofsuch agents by weight of the composition. Examples of inorganicthickening agents to which the above-described negative limitationspertain include finely divided or colloidal silicas, fumed silicas, andsilicates, which includes montmorillonite clays and hydrophobicallytreated montmorillonites, e.g., bentonites, hectorites and colloidalmagnesium silicates. Examples of organic polymeric gelling agents towhich the above-described negative limitations pertain include organicpolymers well known in the antiperspirant or personal care art for usein providing gelling or thickening or other physical or aestheticbenefits to a composition, specific examples of which includehydrogenated butylene/ethylene/styrene copolymer, polyethylene, oxidizedpolyethylene, polyamides, acrylic acid polymers, ethylene acrylatecopolymers, and other organic polymeric gelling agents described inRheological Properties of Cosmetics and Toiletries, Edited by DennisLaba, published by Marcel Dekker, In., New York (1993), whichdescription is incorporated herein by reference.

The term "substituted" as used herein, unless otherwise specified,refers to chemical moieties or substituents known or otherwise suitablefor attachment to the compounds or other chemical materials described orreferred to herein. These substituents include, but are not limited to,those listed and described in C. Hansch and A. Leo, SubstituentConstants for Correlation Analysis in Chemistry and Biology (1979),which listing and description are incorporated herein by reference.Examples of such substituents include, but are not limited to, alkyl,alkenyl, alkoxy, hydroxy, oxo, nitro, amino, aminoalkyl (e.g.,aminomethyl, etc.), cyano, halo (e.g., chlorine, fluorine, bromine,iodine), carboxy, alkoxyaceyl (e.g., carboethoxy, etc.), thiol, aryl,cycloalkyl, heteroaryl, heterocycloalkyl (e.g., piperidinyl,morpholinyl, pyrrolidinyl, etc.), imino, thioxo, hydroxyalkyl, aryloxy,arylalkyl, amides, esters, ethers, combinations thereof, and the like.

The term "n-acyl amino acid derivatives" refers to gellants selectedfrom the group consisting of n-acyl amino acid amides, n-acyl amino acidesters prepared from glutamic acid, lysine, glutamine, apartic acid, andcombinations thereof, and which are specifically disclosed in U.S. Pat.No. 5,429,816.

The terms "alkyl" and "alkenyl" as used herein, unless otherwisespecified, refer to substituted or unsubstituted, branched, cyclic orlinear, hydrocarbons having from 1 to about 22 carbon atoms.

The term "volatile" as used herein refers to materials which have avapor pressure under ambient conditions of at least about 0.2 mm of Hg.Conversely, the term "non-volatile" as used herein refers to materialswhich have no measurable vapor pressure or which have a vapor of lessthan about 0.2 mm of Hg under ambient conditions.

The solid non-polymeric gellant, antiperspirant active and anhydrousliquid carrier components of the gel-solid stick compositions herein arepreferably not refractive index matched, and more preferably have atleast two of such components with refractive indices (η_(D)) that differby at least about 0.02, more preferably by at least about 0.04.

The antiperspirant gel-solid stick compositions of the present inventioncan comprise, consist of, or consist essentially of the essentialelements and limitations of the invention described herein, as well asany of the additional or optional ingredients, components, orlimitations described herein.

As percentages, parts and ratios are by weight of the total composition,unless otherwise specified. All such weights as they pertain to listedingredients are based on the specific ingredient level and, therefore,do not include solvents, carriers, by-products, filler or other minoringredients that may be included in commercially available materials,unless otherwise specified.

Product Characteristics

The antiperspirant gel-solid stick compositions of the present inventionare characterized in terms of product hardness, visible residue index,and a rheology profile defined by a ratio of an elastic to viscousmoduli. Each of these characteristics is defined in accordance with themethodologies and other limitations described hereinafter.

a) Hardness

The antiperspirant gel-solid stick compositions of the present inventionhave a product hardness of from about 500 gram·force to about 5,000gram·force, preferably from about 750 gram·force to about 2,000gram·force, more preferably from about 800 gram·force to about 1,400gram·force.

The term "product hardness" as used herein is a reflection of how muchforce is required to move a penetration cone a specified distance and ata controlled rate into an antiperspirant gel-solid stick compositionunder the following test conditions. Higher values represent harderproduct, and lower values represent softer product. These values aremeasured at 27° C., 15% relative humidity, using a TA-XT2 TextureAnalyzer, available from Texture Technology Corp., Scarsdale, N.Y.,U.S.A. The product hardness value as used herein represents the amountof force required to move a standard 45° angle penetration cone throughthe composition for a distance of 10 mm at a rate of 2 mm/second. Thestandard cone is available from Texture Technology Corp., as part numberTA-15, and has a total cone length of about 24.7 mm, angled cone lengthof about 18.3 mm, a maximum diameter of the angled surface of the coneof about 15.5 mm. The cone is a smooth, stainless steel construction andweighs about 17.8 grams.

b) Residue

The antiperspirant gel-solid stick compositions of the present inventionhave a visible residue index of from 11 to about 30 L-value, preferablyfrom about 11 to about 25 L-value, more preferably from 11 to about 20L-value. The term "visible residue index" as used herein refersgenerally to the extent to which the composition of the presentinvention is visibly apparent as a thin topical film after applicationto the skin, and more specifically refers to visible residue values(expressed as an L-value on the L, a, b color scale) as measured inaccordance with the following methodology, performed at 27° C., underatmospheric pressure, and at 15% relative humidity on antiperspirantstick compositions having a product hardness of from about 500gram·force to about 5,000 gram·force.

A piece of black felt, approximately 10 cm×30 cm, is attached to amovable horizontal slide which is movably attached or fixed to a largermechanical unit. An example of a suitable piece of black felt for useherein is Supreme Robe Velour, FN-6554, Color 404L, Style 31854,available from So-Fro Fabrics, Evendale, Ohio, U.S.A. An example of asuitable mechanical assembly for use herein is the Release and AdhesionTester, Serial No. A-14934, manufactured by Testing Machines, Inc.,Amityville, N.Y., U.S.A., or a Velmex Unislide Positioning System,Unislide assembly series (MB6000), available from Velmex, Inc.,Bloomfield, N.Y., U.S.A. An antiperspirant stick composition containedwithin and partially extending out about 0.5 cm from a conventionalpackage or container is positioned perpendicular to and above theattached piece of felt, such that the product extending out of thepackage or container is facing the piece of felt and the surroundingpackage is positioned away from the piece of felt. The surroundingpackage is positioned in place using a mechanical arm or other devicesuitable for applying the requisite movement to the product as describedherein.

The antiperspirant stick composition is then slowly moved toward andallowed to gently contact the attached piece of black felt. A 1,000 gramweight is placed on the product sample so that the product continuouslycontacts the piece of black felt during testing. The weighted sample isthen moved repeatedly back and forth across the piece of felt at a fixedspeed (about 3 cm/second), and with a fixed amount of applied pressureprovided by the weighted product, until the about 1.75 grams of theantiperspirant stick composition is evenly applied over a 5 cm×20 cmarea of the piece of black felt. The piece of felt is then carefullyremoved from the apparatus.

A calibrated Minolta CR-300 chromameter (available from Minolta Corp.,Ramsey, N.J., U.S.A.) is then used to measure the L-value (on the L,a,bcolor scale) of the applied surface area. First, a template is placed ontop of the piece of felt to facilitate the Minolta readings. Templatedimensions are 5 cm×20 cm. The template has twelve circular openings(2.2 cm diameter) positioned within the template, each openingpositioned centrally within adjacent 6.5 cm² areas of the templatesurface. The template is positioned over the applied surface area of thepiece of felt such that each of the twelve circular openings covers anon-overlapping area of the applied surface. The chromameter's view portis fitted into each of the circular openings and L-value measurementstaken. An average L-value is then determined for the twelve measurements(standard deviation of less than about 0.8) which then corresponds tothe visible residue index as described herein.

It has been found that there is a correlation between the visibleresidue index range defined herein and the average particle size of thecrystalline gellant particles in the antiperspirant gel-solid stickcomposition of the present invention. Generally, as the average particlesize of crystalline gellant particles in the composition decreases, lowresidue performance improves. In particular, it has been found that avisible residue index of from about 11 to about 30 L-value correlateswith an average crystalline gellant particle size of less than about 1μm, and/or a crystalline gellant particle morphology characterized byone dimensional crystalline growth such as that resulting in crystallinefilaments, fibers, strings or other elongated particles, wherein theaspect ratio as defined by the major and minor axis of the crystallineparticle is greater than about 2, preferably greater than about 6.Conversely, solid compositions containing crystalline gellant particlesgreater than 1 μm (average particle diameter) have a visible residueindex of greater than 30 L-value. In view of this correlation betweenvisible residue index values and average crystalline particle size orelongated particle morphology, the visible residue index measurement cannow be used as an alternative means for establishing average crystallinegellant particle size or crystalline gellant morphology, at least to theextent that such average particle size is less than about 1 μm.

c) Rheology

The antiperspirant stick compositions of the present invention aregel-solids having the select rheology profile defined herein. Thisrheology profile is defined herein in terms of the elastic (G') toviscous (G") moduli ratio (G'/G") of the gel-solid stick composition. Toprovide the requisite rheology, the gel-solid stick compositions musthave a G'/G" ratio of from about 0.1 to about 100, preferably from about0.1 to about 50, more preferably from about 1 to about 20, even morepreferably from about 5 to about 20. This ratio represents the extent towhich the gel-solid stick compositions herein exhibit solid characterand the extent to which the compositions exhibit liquid or fluidcharacter, and specifically refers to the numerical ratio G'/G" asdetermined by the following methodology.

The elastic modulus is a measurement which correlates with the solidcharacter of the gel-solid stick compositions herein, and the viscousmodulus is a measurement which correlates with the fluid or liquidcharacter of the gel-solid stick compositions herein. Measurements forG' and G" for purposes of defining the composition of the presentinvention are determined under ambient conditions using conventionaltechniques well known in the formulation arts. For example, a BohlinStress-Strain Rheometer, available from Bohlin Reologi, Cranberry, N.J.,can be used using a cone (about 1°) and plate configuration. About 1.0mg of the product is carefully removed for the composition with minimalapplication of shear force and is then placed between the cone and platefixtures for measurement of G' and G".

It has been found that the gel-solid stick compositions of the presentinvention exhibit improved low residue performance when formulated asdescribed herein, wherein the composition has the select G'/G" ratiodescribed hereinabove, especially when the defined rheology isassociated with a crystalline gel matrix having a preferred smallparticle size and/or particle morphology as described herein. Thesegel-solid stick formulations spread smoothly over the skin, and shearquickly and melt during such spreading to form a thin, low residue filmover the applied surface.

In particular, it has been found that the gel-solid stick compositionsof the present invention have rheology characteristics that result inimproved performance, especially low residue performance. These selectgel-solid compositions as defined herein behave as solids prior toapplication while maintained within a canister or other package, butbehave more as liquids or fluids during or immediately after applicationto the skin. In other words, the solid compositions shear thin duringapplication to the skin, melt or almost melt (except for particulateactive which remains unmelted) during the shear thinning application,thus resulting in a thin, low residue, liquid or fluid film on the skinduring or immediately after topical application to the skin. The appliedfilm is clear or has very low visible residue, and remains substantiallyas such over extended periods of time after application.

Antiperspirant Active

The antiperspirant gel-solid stick compositions of the present inventioncomprise particulate antiperspirant active suitable for application tohuman skin. These particulate actives must remain substantiallyunsolubilized as dispersed or precipitated solids in the anhydrous orsubstantially anhydrous systems as described herein. The concentrationof particulate active in the composition should be sufficient to providethe desired perspiration wetness and odor control from theantiperspirant gel-solid stick formulation selected.

The antiperspirant gel-solid stick compositions of the present inventionpreferably comprise particulate antiperspirant active at concentrationsof from about 0.5% to about 60%, more preferably from about 5% to about35%, by weight of the composition. These weight percentages arecalculated on an anhydrous metal salt basis exclusive of water and anycomplexing agents such as glycine, glycine salts, or other complexingagents. The particulate antiperspirant active as formulated in thecomposition are in the form of dispersed solid particles having apreferred average particle size or diameter of less than about 100 μm,more preferably from about 15 μm to about 100 μm, even more preferablyfrom about 20 μm to about 100 μm. Also preferred are dispersed solidparticulates having an average particle size or diameter of less thanabout 2 μm, even more preferably from less than about 0.4 μm. It hasbeen found that antiperspirant active particles within the preferredparticle size ranges provide lower visible residue performance from thegel-solid compositions herein than other less preferred particle sizeranges.

The antiperspirant active for use in the antiperspirant gel-solid stickcompositions of the present invention include any compound, compositionor other material having antiperspirant activity. Preferredantiperspirant actives include the astringent metallic salts, especiallythe inorganic and organic salts of aluminum, zirconium and zinc, as wellas mixtures thereof. Particularly preferred are the aluminum andzirconium salts, such as aluminum halides, aluminum chlorohydrate,aluminum hydroxyhalides, zirconyl oxyhalides, zirconyl hydroxyhalides,and mixtures thereof.

Preferred aluminum salts for use in the antiperspirant gel-solid stickcompositions include those which conform to the formula:

    Al.sub.2 (OH).sub.a Cl.sub.b.xH.sub.2 O

wherein a is from about 2 to about 5; the sum of a and b is about 6; xis from about 1 to about 6; and wherein a, b, and x may have non-integervalues. Particularly preferred are the aluminum chlorhydroxides referredto as "5/6 basic chlorhydroxide", wherein a=5, and "2/3 basicchlorhydroxide", wherein a=4. Processes for preparing aluminum salts aredisclosed in U.S. Pat. No. 3,887,692, Gilman, issued Jun. 3, 1975; U.S.Pat. No. 3,904,741, Jones et al., issued Sep. 9, 1975; U.S. Pat. No.4,359,456, Gosling et al., issued Nov. 16, 1982; and British PatentSpecification 2,048,229, Fitzgerald et al., published Dec. 10, 1980, allof which are incorporated herein by reference. Mixtures of aluminumsalts are described in British Patent Specification 1,347,950, Shin etal., published Feb. 27, 1974, which description is also incorporatedherein by reference.

Preferred zirconium salts for use in the antiperspirant gel-solid stickcompositions include those which conform to the formula:

    ZrO(OH).sub.2-a Cl.sub.a.xH.sub.2 O

wherein a is from about 1.5 to about 1.87; x is from about 1 to about 7;and wherein a and x may both have non-integer values. These zirconiumsalts are described in Belgian Patent 825,146, Schmitz, issued Aug. 4,1975, which description is incorporated herein by reference.Particularly preferred zirconium salts are those complexes whichadditionally contain aluminum and glycine, commonly known as ZAGcomplexes. These ZAG complexes contain aluminum chlorhydroxide andzirconyl hydroxy chloride conforming to the above described formulas.Such ZAG complexes are described in U.S. Pat. No. 3,679,068, Luedders etal., issued Feb. 12, 1974; Great Britain Patent Application 2,144,992,Callaghan et al., published Mar. 20, 1985; and U.S. Pat. No. 4,120,948,Shelton, issued Oct. 17, 1978, all of which are incorporated herein byreference.

The antiperspirant gel-solid stick compositions of the present inventioncan also be formulated to comprise other dispersed solids or othermaterials in addition to or in place of the particulate antiperspirantactive. Such other dispersed solids or other materials include anymaterial known or otherwise suitable for topical application to humanskin. The antiperspirant gel-solid stick compositions can also beformulated as gel-solid stick compositions which contain noantiperspirant or other active material, particulate or otherwise.

Gellant

The antiperspirant gel-solid stick compositions of the present inventioncomprise a solid non-polymeric gellant suitable for topical applicationto human skin, other than inorganic thickening agents, organic polymericgellants or other gellants such as dibenzylidene alditol and n-acylamino acid derivatives. These solid non-polymeric gellants must formwithin the composition a crystalline matrix within which an anhydrousliquid carrier or other liquid component of the composition is trappedor contained. These solid non-polymeric gellants preferably formcrystalline particles having an average particle diameter and particlemorphology as described hereinafter.

The antiperspirant gel-solid stick compositions are substantially freeof inorganic thickening agents, organic polymeric thickening agents, andgellants selected from the group consisting of dibenzylidene alditols,and n-acyl amino acid derivatives. In this context, "substantially free"means that the compositions contain less than an effective amount ofsuch agents that when used alone would provide any thickening ormeasurable viscosity increase to the composition under ambientconditions. Generally, the compositions preferably contain less than 5%,more preferably less than 1%, even more preferably less than 0.5%, mostpreferably zero percent, of such agents by weight of the composition.

The antiperspirant gel-solid compositions are preferably substantiallyfree of fatty alcohols that are solids under ambient conditions andwhich contain from 12 to 40 carbon atoms. More specifically, thecompositions herein preferably contain no more than about 5%, preferablyfrom zero to about 2%, by weight of such fatty alcohol materials.Minimal concentrations of such materials may be used, however, in thecomposition as a nucleating agent as described hereinafter.

The concentration of the gellants in the compositions may vary with eachselected antiperspirant gel-solid stick formulation, especially witheach selected anhydrous liquid carrier of the formulation, but suchconcentrations will generally range from about 0.1% to about 20%,preferably from about 1% to about 15%, more preferably from about 3% toabout 12%, by weight of the composition. The non-polymeric gellants mustbe solids under ambient conditions.

The solid non-polymeric gellants for use in the antiperspirant gel-solidstick compositions are those which can melt and form a solution or otherhomogenous liquid or liquid dispersion with the selected anhydrousliquid carrier, and at the selected gellant and liquid carrierconcentrations, at a processing temperature of from about 28° C. toabout 250° C., preferably from about 28° C. to about 100° C., morepreferably from about 28° C. to about 78° C. The melted non-polymericgellant is typically dissolved by or dispersed throughout the selectedliquid carrier to thus form a solution or other homogenous liquid. Thesolution or other homogenous liquid, and other essential and optionalingredients, are preferably combined in accordance with themanufacturing method described herein or other conventional or otherwiseknown technique, and then placed in a suitable package as a flowablesolution or homogenous liquid, and then allowed to solidify and form thedesired solid gel matrix within the composition as the temperaturereturns to ambient temperature and drops to below the solidificationpoint of the composition.

In selecting a combination of solid non-polymeric gellant and liquidcarrier for use in the antiperspirant gel-solid stick compositions, theselected combination should allow for the development of a crystallinegellant matrix within the composition wherein the component crystallineparticles preferably have an average particle size of less than about 1μm, more preferably less than about 0.4 μm, even more preferably lessthan about 0.2 μm, most preferably from about 0.001 μm to about 0.2 μm,and/or wherein the crystalline particles have the requisite elongatedmorphology described herein, wherein particle size is measured ordetermined by the methods described herein or by methods well-known tothose skilled in the art such as light or electron microscopy. Thegel-solid stick compositions can be prepared by methods well known inthe formulation art for making gel-solids having minimal crystallineparticle size or the preferred elongated particle morphology. Thegel-solid stick compositions are preferably prepared by the selectmethods described hereinafter directed to minimizing crystallineparticle size and/or establishing the preferred crystalline particlemorphology.

Solid non-polymeric gellants suitable for use in the antiperspirantgel-solid stick compositions of the present invention include fatty acidgellants, esters and amides of fatty acid gellants, hydroxy acids,hydroxy fatty acids, cholesterolic materials, lanolinolic materials, andother amide gellants known for use as gelling agents or which areotherwise described in detail hereinafter. Other crystalline gellantscan be used in the gel-solid stick compositions of the present inventionprovided that such other gellants can be formulated to provide therequisite crystalline gel matrix and product and rheologycharacteristics defined herein.

Other solid non-polymeric gellants suitable for use in theantiperspirant gel-solid stick compositions herein include fatty acidgellants which include, but are not limited to, fatty acid and hydroxyor alpha hydroxy fatty acids, having from about 10 to about 40 carbonatoms, examples of which include 12-hydroxystearic acid,12-hydroxylauric acid, 16-hydroxyhexadecanoic acid, behenic acid, eurcicacid, stearic acid, caprylic acid, lauric acid, isostearic acid, andcombinations thereof. Preferred fatty acid gellants are those having thefatty acid dimer to monomer ratio as described hereinafter.

Preferred solid non-polymeric gellants suitable for use in theantiperspirant gel-solid stick compositions include 12-hydroxystearicacid, esters of 12-hydroxystearic acid, amides of 12-hydroxystearic acidand combinations thereof. These preferred gellants include those whichcorrespond to the following formula: ##STR1## wherein R₁ is OR₂ or NR₂R₃ ; and R₂ and R₃ are hydrogen, or an alkyl, aryl, or arylalkyl radicalwhich is branched linear or cyclic and has from about 1 to about 22carbon atoms; preferably, from about 1 to about 18 carbon atoms. R₂ andR₃ may be either the same or different; however, at least one ispreferably a hydrogen atom. Preferred among these gellants are thoseselected from the group consisting of 12-hydroxystearic acid,12-hydroxystearic acid methyl ester, 12-hydroxystearic acid ethyl ester,12-hydroxystearic acid stearyl ester, 12-hydroxystearic acid benzylester, 12-hydroxystearic acid amide, isopropyl amide of12-hydroxystearic acid, butyl amide of 12-hydroxystearic acid, benzylamide of 12-hydroxystearic acid, phenyl amide of 12-hydroxystearic acid,t-butyl amide of 12-hydroxystearic acid, cyclohexyl amide of12-hydroxystearic acid, 1-adamantyl amide of 12-hydroxystearic acid,2-adamantyl amide of 12-hydroxystearic acid, diisopropyl amide of12-hydroxystearic acid, and mixtures thereof; even more preferably,12-hydroxystearic acid, isopropyl amide of 12-hydroxystearic acid, andcombinations thereof. Most preferred is 12-hydroxystearic acid.

Suitable amide gellants include disubstituted or branched monoamidegellants, monosubstituted or branched diamide gellants, triamidegellants, and combinations thereof, excluding the n-acyl amino acidderivatives selected from the group consisting of n-acyl amino acidamides, n-acyl amino acid esters prepared from glutamic acid, lysine,glutamine, apartic acid, and combinations thereof, and which arespecifically disclosed in U.S. Pat. No. 5,429,816.

Preferred amide gellants for use herein include alkyl amides of di-and/or tri-basic carboxylic acids or anhydrides, concentrations of whichare preferably from about 0.1% to about 25%, preferably of from about 1%to about 15%, more preferably from about 1% to about 10%, by weight ofthe composition. Alkyl amides suitable for use in the antiperspirantgel-solid stick compositions herein include those which conform to theformula: ##STR2## wherein a backbone is formed from the linkage of C',C" and X and wherein a) R₁ is nil, hydroxy, hydrogen, aryl, siloxane orsaturated or unsaturated, substituted or unsubstituted, straight,branched or cyclic chain C₁ -C₂₂ alkyl, C₁ -C₂₂ alkenyl, C₁ -C₂₂ alkoxy,C₁ -C₂₂ alkyl esters, C₁ -C₂₂ alkyl ethers, or C₁ -C₂₂ alkyl substitutedaryl, preferably C₄ -C₁₈ alkyl, C₄ -C₁₈ alkenyl, C₄ -C₁₈ alkoxy, C₄ -C₁₈alkyl esters, C₄ -C₁₈ alkyl ethers, or C₄ -C₁₈ alkyl substituted aryl,more preferably C₁₂ -C₁₈ alkyl, C₁₂ -C₁₈ alkenyl, C₁₂ -C₁₈ alkoxy, C₁₂-C₁₈ alkyl esters, C₁₂ -C₁₈ alkyl ethers, or C₁₂ -C₁₈ alkyl substitutedaryl;

b) R₂, R₄, R₅ and R6 are independently or together, hydrogen, hydroxy,aryl, siloxane or saturated or unsaturated, substituted orunsubstituted, straight, branched or cyclic chain C₁ -C₂₂ alkyl, C₁ -C₂₂alkenyl, C₁ -C₂₂ alkoxy, C₁ -C₂₂ alkyl esters, C₁ -C₂₂ alkyl ethers, orC₁ -C₂₂ alkyl substituted aryl, preferably C₄ -C₁₀ alkyl, C₄ -C₁₀alkenyl, C₄ -C₁₀ alkoxy, C₄ -C₁₀ alkyl esters, C₄ -C₁₀ alkyl ethers, orC₄ -C₁₀ alkyl substituted aryl, more preferably C₄ -C₈ alkyl, C₄ -C₈alkenyl, C₄ -C₈ alkoxy, C₄ -C₈ alkyl esters, C₄ -C₈ alkyl ethers, or C₄-C₈ alkyl substituted aryl;

c) R₃ is nil, hydroxy, hydrogen, saturated or unsaturated, substitutedor unsubstituted, straight, branched or cyclic chain C₁ -C₄ alkyl, C₁-C₄ alkenyl, C₁ -C₄ alkoxy, C₁ -C₄ alkyl esters or C₁ -C₄ alkyl ethers,preferably a C₁ -C₄ alkoxy, hydroxy or hydrogen, more preferably ahydroxy or hydrogen;

d) R₇ and R₈ are independently or together, nil, hydrogen, hydroxy,aryl, siloxane or saturated or unsaturated, substituted orunsubstituted, straight, branched or cyclic chain C₁ -C₂₂ alkyl, C₁ -C₂₂alkenyl, C₁ -C₂₂ alkoxy, C₁ -C₂₂ alkyl esters, C₁ -C₂₂ alkyl ethers, orC₁ -C₂₂ alkyl substituted aryl, preferably C₄ -C₁₀ alkyl, C₄ -C₁₀alkenyl, C₄ -C₁₀ alkoxy, C₄ -C₁₀ alkyl esters, C₄ -C₁₀ alkyl ethers, orC₄ -C₁₀ alkyl substituted aryl, more preferably C₄ -C₈ alkyl, C₄ -C₈alkenyl, C₄ -C₈ alkoxy, C₄ -C₈ alkyl esters, C₄ -C₈ alkyl ethers, or C₄-C₈ alkyl substituted aryl;

e) R₉ is nil or hydrogen;

f) R₁₀ and R₁₁ are independently or together, nil, hydrogen, hydroxy,aryl, siloxane or saturated or unsaturated, substituted orunsubstituted, straight, branched or cyclic chain C₁ -C₆ alkyl, C₁ -C₆alkenyl, C₁ -C₆ alkoxy, C₁ -C₆ alkyl esters, C₁ -C₆ alkyl ethers, or C₁-C₆ alkyl substituted aryl, preferably C₁ -C₄ alkyl, C₁ -C₄ alkenyl, C₁-C₄ alkoxy, C₁ -C₄ alkyl esters, C₁ -C₄ alkyl ethers, C₁ -C₄ alkylsubstituted aryl or hydrogen, more preferably a hydrogen;

g) X is nil, nitrogen, aryl or .paren open-st.CH₂ .paren close-st._(n)where n is an integer from 1 to 6, preferably .paren open-st.CH₂ .parenclose-st._(n) where n is an integer from 1 to 3;

h) Y is nil, acyl or carbonyl;

i) Z is nil, hydrogen, hydroxy, aryl, siloxane, nitrogen or saturated orunsaturated, substituted or unsubstituted, straight, branched or cyclicchain C₁ -C₂₂ alkyl, C₁ -C₂₂ alkenyl, C₁ -C₂₂ alkoxy, C₁ -C₂₂ alkylesters, C₁ -C₂₂ alkyl ethers, or C₁ -C₂₂ alkyl substituted aryl,preferably C₄ -C₁₀ alkyl, C₄ -C₁₀ alkenyl, C₄ -C₁₀ alkoxy, C₄ -C₁₀ alkylesters, C₄ -C₁₀ alkyl ethers, or C₄ -C₁₀ alkyl substituted aryl, morepreferably C₄ -C₈ alkyl, C₄ -C₈ alkenyl, C₄ -C₈ alkoxy, C₄ -C₈ alkylesters, C₄ -C₈ alkyl ethers, or C₄ -C₈ alkyl substituted aryl; and

j) "a" is a double or single bond provided:

(i) when X is nil, Y, Z, R₃, R₇ and R₈ are nil, C' is bonded directly toC" and R₁ is not a hydrogen;

(ii) when X and Z are not nil and Y is nil, X is directly bonded to Z;

(iii) when Z is nil, a hydrogen or a hydroxy, R₇ and R₈ are nil; and

(iv) when "a" is a double bond, R₃ and R₉ are nil.

Alkyl amides of di- and tri-basic carboxylic acids or anhydridessuitable for use in the antiperspirant gel-solid stick compositioninclude alkyl amides of citric acid, tricarballylic acid, aconitic acid,nitrilotriacetic acid, succinic acid and itaconic acid such as1,2,3-propane tributylamide, 2-hydroxy-1,2,3-propane tributylamide,1-propene- 1,2,3-trioctylamide, N,N',N"-tri(acetodecylamide)amine,2-dodecyl-N,N'-dihexylsuccinamide, and 2dodecyl-N,N'-dibutylsuccinamide. Preferred are alkyl amides ofdi-carboxylic acids such as di-amides of alkyl succinic acids, alkenylsuccinic acids, alkyl succinic anhydrides and alkenyl succinicanhydrides, more preferably 2-dodecyl-N,N'-dibutylsuccinamide.

The alkyl amide gelling agents, preferably, have opposing andsubstantially parallel terminal chains extending outward from thegelling agent backbone. It is believed that this spacial arrangement, or"tuning fork" structural configuration, facilitates the formation ofnetworks essential to the formulation of gel or gel-solid stickcompositions. By the phrase "tuning fork configuration", as used hereinmeans any configuration resembling an article or implement having ahandle portion which extends longitudinally at one end to form twoprongs. It is also preferred that the terminal chains be linked to thegelling agent backbone by means of acyl-amide linkages wherein the acylportion of the acyl-amide linkage is directly attached to the gellingagent backbone.

The alkyl amides gellants may be synthesized using either of thefollowing one or two step reaction procedures. The one step procedureinvolves direct amidation of the di- or tri-basic organic acid oranhydride with the appropriate alkyl amine under reaction temperaturestypically at or near the boiling point of the alkyl amine, preferablyfrom about 30° C. to about 200° C., followed by removal of excess amine.Certain reactions, do to their exothermic nature, may not requireexternal heating.

The alkyl amides gellants may also be synthesized using a two stepprocedure which involves esterification of the di- or tri-basic organicacid or anhydride with methanol using a boron trifluoride or other LewisAcid catalyst at a temperature of from about 30° C. to about 100° C.followed by removal of the excess methanol and catalyst. The resultingtrimethyl ester is then amidated as described in the one step processabove using the appropriate alkylamine followed by removal of excessamine. The alkyl amides are preferably non-polymeric.

These solid non-polymeric gellants described herein are especiallyeffective when used in combination with select anhydrous carriers suchas volatile silicones, especially volatile cyclomethicone. Thesegellants are most preferably used in combination with a liquid carriercomprising a volatile silicone and a non-volatile silicone (e.g.,non-volatile dimethicones or other organofunctional siloxanes well knownin the art) and/or a non-volatile organic carrier.

Preferred Enantomeric Gellants

Preferred solid non-polymeric gellants for use herein include thoseenantomeric compounds or materials containing at least one asymmetric(chiral) carbon atom. Non-limiting examples of these preferredenantomeric gellants include 12-hydroxystearic acid, other hydroxy acidssuch as alpha hydroxy acids, cholesterols, lanolin, and derivativesthereof

It has been found that these preferred enantomeric gellants, when usedin the anhydrous antiperspirant gel-solid stick compositions herein,provide the composition with the requisite product hardness, visibleresidue index values and rheological properties (G'/G"). It is believedthat these enantomeric gellants are especially effective in formingone-dimensional elongated particles in the form of filaments, fibrils orstrings which are intertwined or twisted to form a stable,three-dimensional crystalline matrix in the gel-solid composition. Theseelongated particles have an aspect ratio of greater than about 2,preferably greater than about 6. It is believed that these gellants formelongated crystalline particles that result in a stable crystallinematrix that, in part because of the small size and elongated morphologyof these particles, cause less scattering of light when applied to theskin in the antiperspirant composition, which then results in lowvisible residue after such application.

Preferred Particle Morphology

The solid non-polymeric gellants for use herein include thosecrystalline gellants that inherently form, or can be formulated orotherwise made to form, elongated crystalline particles having an aspectratio greater than about 2, preferably greater than about 6. Theseelongated crystals preferably have an average particle size as measuredalong a minor axis of the elongated crystal of less than 1 μm, morepreferably less than about 0.4 μm, even more preferably less than about0.2 μm, most preferably from about 0.2 μm to about 0.001 μm.

The gel-solid stick compositions containing these preferred elongatedcrystals can be prepared by methods described herein, or by methodsotherwise known in the formulation art for formulating gel matricescomprising these elongated crystalline particles.

The "aspect ratio" as used herein to define preferred embodiments of thegel-solid stick compositions herein can be determined by measuring orotherwise determining the ratio of the length of the major axis of thecrystalline particles to the length of the minor axis of the crystallineparticles. This length ratio of the major to minor axis is characterizedas the aspect ratio referred to herein. The aspect ratio can bedetermined by conventional or otherwise known light or electronmicroscopy methods, wherein the crystalline particles are measured formajor and minor axis dimensions, or are otherwise observed by suchmethods to clearly have an apparent elongated crystalline structure withan aspect ratio substantially greater than about 2, preferably greaterthan about 6.

It has been found that these crystalline gellants having the selectaspect ratios defined herein, provide the antiperspirant gel-solid stickcompositions a three-dimensional crystalline structure that can providethe composition with the requisite low residue performance, elastic toviscous moduli ratio, and product hardness as defined herein. It isbelieved that this crystalline morphology is especially effective inproviding a crystalline matrix within the composition that provides fora strong interlocking gel-solid matrix network, but which also comprisescrystalline particles that are sufficiently small in size so as tocontribute minimally to visible residue when applied topically to theskin.

It has also been found that the preferred crystalline matrix helpsprovide the gel-solid stick compositions with a melt profile thatcontributes to low residue performance. This preferred melt profilerefers to the temperature at which the antiperspirant gel-solid stickcomposition begins to melt, and the temperature range within which thecomposition is completely melted, except for any dispersedantiperspirant particulates or other high melting point components. Thetemperature at which the composition begins to melt is determined bymeasuring a Differential Scanning Calorimeter (DSC) onset temperature.The temperature range within which the composition is completely meltedis determined by no additional heat infusion. Preferred embodiments ofthe gel-solid stick compositions herein have a DSC onset temperature offrom about 25° C. to about 85° C., preferably from about 27° C. to about65° C., more preferably from about 30° C. to about 60° C., even morepreferably from about 35° C. to about 50° C. These preferredcompositions having the select melt profile provide improved cosmeticsor aesthetics when applied topically to the skin, and especially providereduced feeling of wetness, stickiness or product softness during andimmediately after application. The select melt profile also helps tofurther reduce the visible residue index of the composition, thusfurther improving lower residue performance.

Preferred Dimer to Monomer Ratio

The solid non-polymeric gellant of the antiperspirant gel-solid stickcompositions herein preferably comprise a fatty acid gellant having aselect dimer-to-monomer ratio. The fatty acid gellants having therequisite dimer-to-monomer ratio may be used alone or in combinationwith an additional or secondary gellant in the composition. The selectdimer-to-monomer ratio helps provide the gel-solid stick compositionsherein with improved low residue performance, efficacy and aesthetics,and especially provides for improved low residue performance andimproved product hardness.

The fatty acid gellants in the antiperspirant gel-solid stickcomposition, when used in combination with an additional or secondarygellant, has a select dimer-to-monomer ratio of from about 1:1 to about25:1, preferably from about 1.5:1 to about 25:1, more preferably fromabout 2.5:1 to about 20:1, even more preferably from about 3:1 to about10:1. The higher dimer-to-monomer ratios are preferred.

The dimer-to-monomer ratio of the fatty acid gellant can be determinedby methods or techniques known in the formulation arts, includinginfrared methods such as Fourier Transform Infared (FTIR) Spectroscopy.Such methods are disclosed in The Infared Spectra of Complex Molecules,L. J. Bellamy, 2nd Edition, 1958, Introduction to Infared and RamanSpectroscopy, N. B. Colthup, et. al., 3rd Edition, 1990, and FourierTransform Infared Spectroscopy, P. R. Griffiths, et. al., 1986, alldisclosures of which are incorporated by reference herein. In accordancewith such methods or techniques, fatty acids are usually characterizedby their carbonyl stretching frequencies which are measured asabsorption bands between 1740 cm⁻¹ and 1680 cm⁻¹. The fatty acid gellantof the antiperspirant composition of the present invention comprisesfatty acid dimers and fatty acid monomers which are components of thecarbonyl absorption band. However, due to the formation of hydrogenbonded dimers, the fatty acid dimer component can be shifted as far as30 cm⁻¹ frequencies lower than the fatty acid monomer frequency.

By use of infrared spectra data, the dimer-to-monomer ratio isdetermined by calculating the ratio of the peak area of the hydrogenbonded dimer second derivative band near 1696 cm⁻¹ to the peak area ofthe fatty acid monomer second derivative band near 1712 cm⁻¹. Inaccordance with the following methodology, an infrared spectra isrecorded using a 45° ZnSe Attenuated Total Reflectance ("ATR" herein)crystal and a horizontal ATR apparatus (available from Spectra Tech,Inc., Shelton, Conn., U.S.A.) attached to a Nicolet 20scx FTIRSpectrometer. The Nicolet 20scx FTIR Spectrometer is available fromNicolet Instrument Corporation, Madison, Wis., U.S.A. The Nicolet 205scxFTIR Spectrometer is equipped with a narrow band mercury cadmiumTelluride detector whereby an average of 256 scans are co-added togenerate the infrared spectra. The infrared spectra is then importedinto a computer software program such as GRAMS/386 (available fromGalactic Industries Corporation, Salem, N.H., U.S.A.) to calculate thedimer-to-monomer ratio using a 5 point second derivative algorithm whichis a mathematical procedure defined by Savitsky-Golay.

The requisite dimer-to-monomer ratio may be established with the fattyacid gellants described herein, which includes alpha-hydroxy fatty acidsand fatty acids having from about 10 to about 40 carbon atoms, examplesof which include 12-hydroxystearic acid, 12-hydroxylauric acid,16-hydroxyhexadecanoic acid, behenic acid, eurcic acid, stearic acid,caprylic acid, lauric acid, isostearic acid, and combinations thereof.Examples of some suitable fatty acid gellants are described in U.S. Pat.No. 5,429,816, issued to Hofrichter et al. on Jul. 4, 1995; and U.S.Pat. No. 5,552,136, issued to Motley on Sep. 3, 1996, which descriptionsare incorporated herein by reference. Most preferred is12-hydroxystearic acid.

The requisite dimer-to-monomer ratio may also be established with thefatty acid gellants described herein in combination with an additionalor secondary gellant, wherein the molar ratio of the fatty acid gellantto the additional or secondary gellant is from about 1:2 to about 20:1,preferably from about 1:1 to about 10:1, more preferably from about 2:1to about 7:1, and even more preferably from about 3:1 to about 5:1. Oneof average skill in the chemical or formulation arts can formulate thesefatty acid gellant systems to control or otherwise obtain the desiredratio. The additional or secondary gellants suitable for use informulating the requisite dimer-to-monomer ratio include the other solidnon-polymeric gellants described herein.

Anhydrous Liquid Carrier

The anhydrous antiperspirant gel-solid stick compositions of the presentinvention comprise an anhydrous carrier which is liquid under ambientconditions, and which contains a modified silicone carrier selected fromthe group consisting of polyalkylsiloxanes, polyalkyarylsiloxanes,polyestersiloxanes, polyethersiloxane copolymers, polyfluorosiloxanes,polyaminosiloxanes, and combinations thereof.

Concentrations of the anhydrous liquid carrier in the gel-solid stickcomposition will vary primarily with the type and amount of theanhydrous liquid carrier, the solid non-polymeric gellant, and thesolubility of the solid non-polymeric gellant in the anhydrous liquidcarrier. Preferred concentrations of the anhydrous liquid carrier arefrom about 10% to about 80%, preferably from about 30% to about 70%,more preferably from about 45% to about 70%, by weight of thecomposition. Concentrations of the modified silicone carrier componentof the anhydrous liquid carrier is from about 0.1% to about 80%,preferably from about 0.1% to about 50%, more preferably from about 1%to about 20%, and even more preferably from about 1% to about 10%, byweight of the antiperspirant gel-solid stick composition.

The anhydrous liquid carrier preferably comprises one or more othercarrier liquids other than and in addition to the modified siliconecarriers described herein. These other carrier liquids should besuitable for topical application to human skin, and may include organicor silicone-containing or fluorine-containing, volatile or non-volatile,polar or non-polar, carrier liquids, provided that the resultinganhydrous liquid carrier forms a solution or other homogenous liquid orliquid dispersion with the selected non-polymeric gellant at theselected gellant concentration at a temperature of from about 28° C. toabout 250° C., preferably from about 28° C. to about 100° C., preferablyfrom about 28° C. to about 78° C.

The anhydrous liquid carrier has a solubility parameter of from about 3to about 13 (cal/cm³)⁰.5, preferably from about 5 to about 11(cal/cm³)⁰.5, more preferably from about 5 to about 9 (cal/cm³)⁰.5.Solubility parameters for the liquid carriers or other materials, andmeans for determining such parameters, are well known in the chemicalarts. A description of solubility parameters and means for determiningthem are described by C. D. Vaughan, "Solubility Effects in Product,Package, Penetration and Preservation" 103 Cosmetics and Toiletries47-69, October 1988; and C. D. Vaughan, "Using Solubility Parameters inCosmetics Formulation", 36 J. Soc. Cosmetic Chemists 319-333,September/October, 1988, which descriptions are incorporated herein byreference.

These modified silicone carriers for use in the antiperspirant gel-solidstick composition must be liquid under ambient conditions, and have aviscosity of less than about 100,000 centistokes, preferably less thanabout 500 centistokes, more preferably from about 1 centistoke to about50 centistokes, and even more preferably from about 1 centistoke toabout 20 centistokes. These modified silicone carriers are generallyknown in the chemical arts, some examples of which are described in 1Cosmetics, Science and Technology 27-104 (M. Balsam and E. Sagarin ed.1972); U.S. Pat. No. 4,202,879, issued to Shelton on May 13, 1980; U.S.Pat. No. 5,069,897, issued to Orr on Dec. 3, 1991; which descriptionsare incorporated herein by reference.

The modified silicone carriers suitable for use in the antiperspirantgel-solid stick compositions include, but are not limited to, compoundsor materials as defined hereinabove and which are generallycharacterized as follows: silicone polyethers or silicone glycols (suchas dimethicone copolyol); silicone alkyl-linked polyethers (such asGoldschmidt EM-90 or EM-97); siloxane surfactants of a pendant/rake/combconfiguration, silicone surfactants of a trisiloxane configuration, andsilicone surfactants of an ABA/alpha-omega block copolymers (such aspolyoxyalkylenes, polyoxyethylene or ethoxylated,polyoxyethylene/polyoxypropylene or ethoxylated/propoxylated); aromaticsubstituted silicone emollients (such as phenyl, alpha-methyl styryl,styryl, methylphenyl, alkylphenyl); silicone copolymers with otherfunctional groups include: hydrogen, alkyl, methyl, amino,trifluoropropyl, vinyl, alkoxy, arylalkyl, aryl, phenyl, styryl,polyethers, esters, carboxylics; alkylmethyl siloxanes or silicone waxes(such as hexyl, octyl, lauryl, cetyl, stearyl); nonionic functionalsiloxane copolymers with terminal groups being silanol ortrimethylsiloxy; nonionic functional siloxanes with backbone groupsbeing trisiloxane or methicone linked; nonionic silicone surfactants;tetraethoxysilane; tetramethoxysilane; hexamethoxysilicone;oxmethoxytrisiloxane; silicone emulsifiers; silicone or siloxane resins,alkyl silicone resins, polyoxyalkylene silicone resins; MQ Resins suchas Shiseido/Shin-etsu, e.g. Japanese Patent Publication JP86143760 orfrom Walker Chem. 6MBH (described in EP722970); alkoxysiloxanes;alkoxysilanes; methicones (polymethylalkylsiloxanes); and combinationsthereof.

Nonlimiting examples of suitable modified silicone carriers for use inthe antiperspirant gel-solid stick compositions herein include thefollowing modified silicones available from Dow Corning: DC-556 CosmeticGrade Fluid (phenyl trimethicone); DC-704 Diffusion Pump Fluid(Tetramethyl-Tetraphenyl-Trisiloxane); DC-705 Diffusion Pump Fluid;DC-1784 Emulsion; DC-AF Emulsion; DC-1520-US Emulsion; DC-593 Fluid(Dimethicone and! Trimethylsiloxysilicate); DC-3225C Fluid(Cyclomethicone and! Dimethicone Copolyol); DC-190 Fluid (DimethiconeCopolyol); DC-193 Fluid (Dimethicone Copolyol); DC-1401 (Cyclomethiconeand! Dimethiconol); DC-5200 Fluid (Laurylmethicone Copolyol); DC-6603Polymer Powder; DC-5640 Powder; DC-Q2-5220 (Dimethicone Copolyol); DCQ2-5324 (Dimethicone Copolyol); DC-2501 Cosmetic Wax (DimethiconeCopolyol); DC-2502 Fluid (Cetyl Dimethicone); DC-2503 Wax (StearylDimethicone); DC-1731 Volatile Fluid (Caproyl Trimethicone); DC-580 Wax(Stearoxytrimethylsilane and! Stearyl Alcohol); DC-1-3563(Dimethiconal); DC-X2-1286 (Dimethiconol); DC-X2-1146A (Cylcomethiconeand! Dimethiconol); DC-8820 Fluid (Amino functionalized); DC Q5-0158Awax (stearoxytrimethylsilane); DC-Q2-8220(Trimethylsilylamodimethicone); DC-7224 (Trimethylsilylamodimethicone);DC-X2-1318 Fluid (Cyclomethicone and! Vinyldimethicone); DC-QF1-3593Afluid (Trimethylsiloxysilicate) and combinations thereof.

Other nonlimiting examples of suitable modified silicone carriers foruse in the antiperspirant gel-solid stick compositions herein includethe following modified silicones available from General Electric: GESF-1023 (Dimethyl-Diphenyl-Siloxane); GE CF-1142 (Methylphenyl SiloxaneFluid); GE SF-1153 (Dimethyl-Diphenyl-Siloxane); GE SF-1265(Diphenyl-Dimethyl-Siloxane); GE SF-1328; GE SF-1188 (Dimethiconecopolyol); GE SF-1188A (Silicone polyether copolymer); GE SF-1288(silicone polyether copolymer, dimethyl-methyl 3-hydroxypropylethoxylated); GE SF-1318 (Methylester Siloxane); GE SF-1328 (siliconesurfactant, dimethyl-methyl 3-hydroxypropyl ethoxylated-propoxylated);GE SF-1550 (methylphenyl siloxane, hexamethyl-3-phenyl-3-trimethylsilyl!oxy!trisiloxane); GE SF-1632 (silicone wax); GE SS-4267(Dimethicone and! Trimethylsiloxysilicate) and combinations thereof.

Other nonlimiting examples of suitable modified silicone carriers foruse in the antiperspirant gel-solid stick compositions herein includethe following modified silicones available from Goldschmidt: Abil EM-90(silicone emulsifier); Abil EM-97 (polyether siloxane); Abil Wax 9810(silicone wax or C24-28 methicone); Abil Wax 2434 (StearoxyDimethicone); Abil Wax 9800D (Stearyl Dimethicone); Tegomer H-Si 2111,H-Si 2311, A-Si 2120, A-Si 2320, C-Si 2141, C-Si 2341, E-Si 2130, E-Si2330, V-Si 2150, V-Si 2550, H-Si 6420, H-Si 6440, H-Si 6460 (Alpha-OmegaDimethicone Copolymers) and combinations thereof.

Other nonlimiting examples of suitable modified silicone carriers foruse in the antiperspirant gel-solid stick compositions herein includethe following: Masil 756 from PPG Industries (TetrabutoxypropylTrisiloxane); bis-phenylhexamethicone (available as Silbione Oils 70633V30 from Rhone-Poulenc); Silbione Oils 70646 (dimethicone copolyols fromRhone-Poulenc); Silicone L-711, L-720, L-721 and L722 (dimethiconecopolyols from Union Carbide); Silicone L-7000, L-7001, L-7002, L-7004,L-7500, L-7600, L-7602, L-7604, L-7605, and L-7610 (dimethiconecopolyols from Union Carbide); Unisil SF-R (dimethiconol from UPI);Silicate Cluster from Olin (Tris tributoxysiloxy!methylsilane); siliconecopolymer F-754 (dimethicone copoly from SWS Silicones); andcombinations thereof.

The anhydrous liquid carrier preferably comprises a volatile siliconecarrier in combination with the modified silicone carrier. Thesevolatile silicone carriers may be cyclic, linear or branched chainsilicones having the requisite volatility defined herein. Non-limitingexamples of suitable volatile silicones are described in Todd et al.,"Volatile Silicone Fluids for Cosmetics", Cosmetics and Toiletries,91:27-32 (1976), which descriptions are incorporated herein byreference. Preferred among these volatile silicones are the cyclicsilicones having from about 3 to about 7, more preferably from about 4to about 5, silicon atoms. Most preferably are those which conform tothe formula: ##STR3## wherein n is from about 3 to about 7, preferablyfrom about 4 to about 5, most preferably 5. These volatile cyclicsilicones generally have a viscosity value of less than about 10centistokes. All viscosity values described herein are measured ordetermined under ambient conditions, unless otherwise specified.Suitable volatile silicones for use herein include, but are not limitedto, Cyclomethicone D-5 (commercially available from G. E. Silicones);Dow Corning 344, and Dow Corning 345 (commercially available from DowCorning Corp.); GE 7207, GE 7158 and Silicone Fluids SF-1202 and SF-1173(available from General Electric Co.); SWS-03314, SWS-03400, F-222,F-223, F-250, F-251 (available from SWS Silicones Corp.); VolatileSilicones 7158, 7207, 7349 (available from Union Carbide); Masil SF-V(available from Mazer) and combinations thereof.

The anhydrous liquid carrier may also comprise a non-volatile siliconecarrier in combination with the modified silicone carriers describedhereinbefore. These non-volatile silicone carriers are preferably linearsilicones which include, but are not limited to, those which conform toeither of the formulas: ##STR4## wherein n is greater than or equalto 1. These linear silicone materials will generally have viscosityvalues of up to about 100,000 centistoke, preferably less than about 500centistoke, more preferably from about 1 centistoke to about 200centistoke, even more preferably from about 1 centistoke to about 50centistoke, as measured under ambient conditions. Examples ofnon-volatile, linear silicones suitable for use in the antiperspirantcompositions include, but are not limited to, Dow Corning 200,hexamethyldisiloxane, Rhodorsil Oils 70047 available from Rhone-Poulenc,Masil SF Fluid available from Mazer, Dow Coming 225, Dow Corning 1732,Dow Corning 5732, Dow Corning 5750 (available from Dow Corning Corp.);SF-96, SF-1066 and SF18(350) Silicone Fluids (available from G. E.Silicones); Velvasil and Viscasil (available from General Electric Co.);and Silicone L-45, Silicone L530, Silicone L-531 (available from UnionCarbide), and Siloxane F-221 and Silicone Fluid SWS-101 (available fromSWS Silicones).

The anhydrous liquid carrier may further comprise, but is preferablysubstantially free of, organic, water-immiscible, polar liquid carriersor solvents in combination with the modified silicone carrier. It hasbeen found that the antiperspirant and deodorant efficacy of thegel-solid stick compositions are improved by minimizing or eliminatingthe amount or concentration of these polar, organic, water-immiscible,liquid carriers or solvents in the composition. In this context, theterm "substantially free" means that the antiperspirant gel-solid stickcompositions preferably contain less than 7%, more preferably less thanabout 3%, even more preferably zero percent, by weight of an organic,water-immiscible, polar liquid carrier or solvent. These organic polarsolvents are liquid under ambient conditions and include mono andpolyhydric alcohols, fatty acids, esters of mono and dibasic carboxylicacids with mono and polyhydric alcohols, polyoxyethylenes,polyoxypropylenes, polyalkoxylates ethers of alcohols, and combinationsthereof, provided that such solvents are also water-immiscible liquidsunder ambient conditions. Examples of some organic, water-immiscible,polar liquid carriers or solvents are described in Cosmetics, Science,and Technology, Vol. 1, 27-104, edited by Balsam and Sagarin (1972);U.S. Pat. No. 4,202,879 issued to Shelton on May 13, 1980; and U.S. Pat.No. 4,816,261 issued to Luebbe et al. on March 28, 1989, whichdescriptions are incorporated herein by reference.

The anhydrous liquid carrier may also comprise an anhydrous,water-miscible, polar organic liquid carrier or solvent in combinationwith the modified silicone carrier, examples of which include shortchain alcohols such as ethanol. These and other polar organic carriersor solvents can be used as co-solvents for the solid non-polymericgellant component of the antiperspirant gel-solid stick compositionsherein. Non-limiting examples of polar co-solvents suitable for useherein are described in U.S. Pat. No. 5,429,816. Other suitable polarco-solvents include those described hereinabove, which are preferablywater-immiscible organic solvents, and other co-solvents such asphthalate co-solvents, benzoate co-solvents, cinnamate esters, secondaryalcohols, benzyl acetate, phenyl alkane and combinations thereof.

The anhydrous liquid carrier may also comprise other non-polar carriersin combination with the modified silicone carrier. Examples of suchother non-polar carriers include mineral oil, petrolatum, isohexadecane,isododecane, various hydrocarbon oils such as the Isopar or Norparseries available from Exxon Corp. or Permethyl series available fromPersperse, and any other polar or non-polar, water-miscible, organiccarrier liquid or solvent known or otherwise safe and effective fortopical application to human skin.

The anhydrous liquid carrier may also comprise fluorochemicals inaddition to or in place of the modified silicone carrier. Thesefluorochemicals include fluorosurfactants, fluorotelemers, andperfluoropolyethers, some examples of which are described in Cosmetics &Toiletries, Using Fluorinated Compounds in Topical Preparations, Vol.111, pages 47-62, (October 1996) which description is incorporatedherein by reference. More specific examples of such liquid carriersinclude, but are not limited to, perfluoropolymethyl isopropyl ethers,perfluoropolypropylethers, acrylamide fluorinated telomer, fluorinatedamide surfactants, perfluorinated thiol surfactants. Other more specificexamples include, but are not limited to, the polyperfluoroisopropylethers available from Dupont Performance Chemicals under the trade nameFluortress® PFPE oils, and the series fluorosurfactants from DupontPerformance Chemicals under the trade name Zonyl® Fluorosurfactants.

Optional Nucleating Agent

The antiperspirant gel-solid stick compositions of the present inventionpreferably further comprises a nucleating agent. The nucleating agent isused to minimize gellant particle size, and/or for obtaining thepreferred gellant particle morphology described herein.

The nucleating agent for use in the antiperspirant composition of thepresent invention must be a solid material under ambient conditions andhave 1) a melting point near the melting point of the selected gellant,2) a solubility in the anhydrous liquid carrier that is less than thesolubility of the solid non-polymeric gellant in the anhydrous liquidcarrier, or 3) be in the form of an inorganic, insoluble, micronizedparticulate. Examples of suitable nucleating agents are describedhereinafter.

The concentration of the nucleating agent in the composition istypically from about 0.0001% to about 5%, preferably from about 0.001%to about 2%, more preferably from about 0.01% to about 1%, wherein themolar ratio of the solid non-polymeric gellant to the nucleating agentis from about 10:1 to about 1000:1, preferably from about 10:1 to about100:1. Preferred nucleating agents are those having a melt point of fromabout 40° C. below to about 200° C. above, more preferably from about20° C. below to about 100° C. above, the melting point of the selectedsolid non-polymeric gellant.

The antiperspirant compositions containing the nucleating agent arepreferably prepared by 1) combining the solid non-polymeric gellant,anhydrous liquid carrier and a nucleating agent as described herein, 2)heating components or the combination of components to form a solutionor other homogeneous liquid or liquid dispersion, and 3) solidifying thecombination of components by cooling the combination to below thesolidification point of the solid non-polymeric gellant to form theantiperspirant composition of the present invention. During thisprocess, the solid non-polymeric gellant is preferably melted orotherwise liquefied, and then allowed to solidify in the presence of theanhydrous liquid carrier and the nucleating agent. Also during thisprocess, the nucleating agent is typically melted or otherwise liquefied(except for micronized, inorganic nucleating agents), and then in thepresence of the anhydrous liquid carrier and the melted or liquefiedgellant, the liquified nucleating agent crystallizes, gels or otherwisesolidifies and acts as a seed or nucleus to promote formation of smallgellant nuclei during the crystallization of the gellant in theanhydrous liquid carrier.

The nucleating agent for use in the antiperspirant compositions includefatty alcohols, esters of fatty alcohols, ethoxylated fatty alcohols,esters or ethers of fatty acids including waxes, and triglycerides,silica, titanium dioxide, solid polyol carboxylic acid polyesters, andmixtures thereof.

Suitable fatty alcohols for use as nucleating agents include monohydricalcohols, ethoxylated fatty alcohols, and fatty alcohol esters. Specificexamples of commercially available fatty alcohol nucleating agentsinclude, but are not limited to, Unilin 550, Unilin 700, Unilin 425,Unilin 400, Unilin 350, and Unilin 325, all supplied by Petrolite.Suitable ethoxylated fatty alcohols include, but are not limited,Unithox 325, Unithox 400, and Unithox 450, Unithox 480, Unithox 520,Unithox 550, Unithox 720, Unithox 750, all of which are available fromPetrolite. Non-limiting examples of suitable esters of fatty alcoholsinclude tri-isostearyl citrate, ethyleneglycol di-12-hydroxystearate,tristearylcitrate, stearyl octanoate, stearyl heptanoate,trilaurylcitrate.

Suitable fatty acid esters for use as nucleating agents include esterwaxes, monoglycerides, diglycerides, triglycerides and mixtures thereof.Preferred are the glyceride esters. Non-limiting examples of suitableester waxes include stearyl stearate, stearyl behenate, palmitylstearate, stearyl octyldodecanol, cetyl esters, cetearyl behenate,behenyl behenate, ethylene glycol distearate, ethylene glycoldipalmitate, and beeswax. Examples of commercial ester waxes includeKester waxes from Koster Keunen, Crodamol SS from Croda and DemalcareSPS from Rhone Poulenc.

Preferred triglyceride nucleating agents include, but are not limitedto, tristearin, tribehenate, behenyl palmityl behenyl triglyceride,palmityl stearyl palmityl triglyceride, hydrogenated vegetable oil,hydrogenated rape seed oil, castor wax, fish oils, tripalmiten,Syncrowax HRC and Syncrowax HGL-C (Syncrowax is available from Croda,Inc.). Other suitable glycerides include, but are not limited to,glyceryl stearate and glyceryl distearate.

Preferably, the nucleating agent is a solid polyol carboxylic acidpolyester. Suitable solid polyol carboxylic acid polyesters includethose which are polyol esters or polyesters wherein the carboxylic acidester groups of the polyester comprise a combination of: (a) long chainunsaturated carboxylic acid moieties or a mixture of long chainunsaturated carboxylic acid moieties and short chain saturatedcarboxylic acid moieties, and (b) long chain saturated carboxylic acidmoieties, the ratio of (a) to (b) being from about 1 to 15 to about 2to 1. At least about 15%, preferably at least about 30%, more preferablyat least about 50%, and most preferably at least about 60% by weight ofthe total carboxylic acid moieties of the polyesters are C20 or highersaturated carboxylic acid moieties. The long chain unsaturatedcarboxylic acid moieties are typically straight chain and contain atleast about 12, preferably about 12 to about 26, more preferably about18 to about 22 carbon atoms. The most preferred unsaturated carboxylicacids are the C18 mono and/or di unsaturated carboxylic acids. The shortchain saturated carboxylic acids are typically unbranched and containabout 2 to about 12, preferably about 6 to about 12, and most preferablyabout 8 to about 12 carbon atoms. The long chain saturated carboxylicacids are typically straight chain and contain at least about 20,preferably about 20 to about 26, and most preferably about 22 carbonatoms. The molar ratio of Group (a) carboxylic acid moieties to Group(b) carboxylic acid moieties in the polyester molecule is from about1:15 to about 2:1, preferably about 1:7 to about 5:3, and morepreferably about 1:7 to about 3:5. The average degree of esterificationof these carboxylic acid esters is such that at least about 2 of thehydroxyl groups of the polyol are esterified. In the case of sucrosepolyesters from about 7 to about 8 of the hydroxyl groups of the polyolare preferably esterified. Typically, substantially all, e.g., at leastabout 85%, preferably at least about 95%, of the hydroxyl groups of thepolyol are esterified.

Preferred polyols of the solid polyol carboxylic acid esters are sugars,including monosaccharides and disaccharides and trisaccharides,containing from about 4 to about 11 hydroxyl groups. Most preferredsugars are those which contain about 4 to about 8, more preferably about6 to about 8 hydroxyl groups. Examples of those containing four hydroxylgroups are the monosaccharides xylose, arabinose, and combinationsthereof. Suitable five hydroxyl group-containing polyols are themonosaccharides galactose, fructose, mannose, glucose, and combinationsthereof. Examples of disaccharide polyols which can be used includemaltose, lactose, sucrose, and combinations thereof, all of whichcontain eight hydroxyl groups. The preferred polyol is sucrose.

Examples of long chain unsaturated carboxylic acid moieties include, butare not limited to, lauroleate, myristoleate, palmitoleate, oleate,elaidate, erucate, linoleate, linolenate, arachidonate,eicosapentaentoate, and docosahexaenoate. For oxidative stability, themono- and diunsaturated fatty acid moieties are preferred.

Examples of suitable short chain saturated carboxylic acid moietiesinclude, but are not limited to, acetate, caproate, caprylate, caprate,and laurate.

Examples of suitable long chain saturated carboxylic acid moietiesinclude, but are not limited to, arachidate, behenate, lignocerate, andcerotate.

Of course, the long chain unsaturated carboxylic acid moieties can beused singly or in mixtures with each other or in mixtures with the shortchain saturated carboxylic acid moieties, in all proportions. Likewise,the long chain saturated carboxylic acid moieties can be used incombination with each other in all proportions. Mixed carboxylic acidmoieties from source oils which contain substantial amounts of thedesired unsaturated or saturated acids can be used as the acid moietiesto prepare compounds for use as nucleating agents herein. The mixedcarboxylic acids from the oils should contain at least about 30%,preferably at least about 50%, and most preferably at least about 80% ofthe desired unsaturated or saturated acids. For example, rapeseed oilfatty acids or soybean oil fatty acids can be used instead of pureC12-C16 unsaturated fatty acids. Hardened, i.e. hydrogenated, higherucic rapeseed oil fatty acids can be used instead of pure C20-C26saturated acids, Preferably the C20 and higher acids, or theirderivatives, e.g. methyl or other low alkyl esters, are concentrated forexample by distillation. The fatty acids from palm kernal oil or coconutoil can be used as a source of C8 to C12 acids. An example of the use ofsource oils to make solid polyol polyesters for use in theantiperspirant compositions herein is the preparation of solid sucrosepolyester, employing the fatty acids of high oleic sunflower oil andsubstantially completely hydrogenated high erucic rapeseed oil. Whensucrose is substantially completely esterified with a 1:3 by weightblend of the methyl esters of the fatty acids of these two oils, theresulting sucrose polyester will have a molar ratio of unsaturated C18acid radicals to C20 and higher saturated acid radicals of about 1:1 andabout 28.6 weight percent of the total fatty acids in the polyester willbe C22 fatty acids.

The higher the proportions of the desired unsaturated and saturatedacids in the carboxylic acid stocks used in making the solid polyolpolyester, the more efficient the ester will be in its ability tofunction as a nucleating agent.

Examples of solid polyol carboxylic acid polyester nucleating agents foruse in the antiperspirant composition herein include, but are notlimited to, the octaester of raffinose in which the esterifyingcarboxylic acid moieties are linoleate and behenate in a 1:3 molarratio; the heptaester of maltose wherein the esterifying carboxylic acidmoieties are sunflower seed oil fatty acids and lignocerate in a 3:4molar ratio; the octaester of sucrose wherein the esterifying carboxylicacid moieties are oleate and behenate in a 2:6 molar ratio; and theoctaester of sucrose wherein the esterfying carboxylic acid moieties arelaurate, linoleate and behenate in a 1:3:4 molar ratio. A preferredmaterial is sucrose polyester in which the degree of esterification is7-8, and in which the fatty acid moieties are C18 mono- and/ordi-unsaturated and behenic, in a molar ratio of unsaturates:behenic of1:7 to 3:5. A particularly preferred polyol ester nucleating agent isthe octaester of sucrose in which there are about 7 behenic fatty acidmoieties and about 1 oleic moiety in the molecule.

The solid carboxylic acid polyesters herein can be made according toprior art known methods for preparing polyesters of polyols. See, forexample U.S. Pat. No. 5,306,516, to Letton et al., issued Apr. 26, 1994;U.S. Pat. No. 5,306,515, to Letton et al., issued Apr. 26, 1994; U.S.Pat. No. 5,305,514, to Letton et al., issued Apr. 26, 1994; U.S. Pat.No. 4,797,300, to Jandacek et al., issued Jan. 10, 1989; U.S. Pat. No.3,963,699, to Rizzi et al., issued Jun. 15, 1976; U.S. Pat. No.4,518,772, to Volpenhein, issued May 21, 1985; and U.S. Pat. No.4,517,360, to Volpenhein, issued May 21, 1985; all of which areincorporated by reference herein in their entirety.

Suitable inorganic, micronized, non-solubilized nucleating agents foruse in the antiperspirant compositions include materials such as silica,titanium dioxide and combinations thereof. These materials containsubmicron particles (average particle size generally less than about 1μm) which aid in the production of small gellant crystals or particles.

Preferred nucleating agents, and preferred concentrations of thenucleating agents, for use in the antiperspirant compositions includeC18 succinic acid (0.1%), 1,9-nonanedioc acid (0.1%), Teflon (0.1%),silica (0.1%), polysiloxane copolymer (2%), sucrose octabehenate (0.5%,0.75%, 1.0%), Unilin 350 (0.1%), Unilin 550 (0.1%), Unilin 700 (0.1%),trihydroxystearin (0.1%) and combinations thereof.

Optional Components

The antiperspirant gel-solid stick compositions of the present inventionmay further comprise one or more optional components which may modifythe physical, chemical or aesthetic characteristics of the compositionsor serve as additional "active" components when deposited on the skin.The compositions may also further comprise optional inert ingredients.Many such optional materials are known in the antiperspirant art and maybe used in the antiperspirant compositions herein, provided that suchoptional materials are compatible with the essential materials describedherein, or do not otherwise unduly impair product performance.

Non-limiting examples of optional materials include active componentssuch as bacteriostats and fungiostats, and "non-active" components suchas colorants, perfumes, emulsifiers, chelants, distributing agents,preservatives, residue masking agents, process aides such as viscositymodifiers, and wash-off aids. Examples of such optional materials aredescribed in U.S. Pat. No. 4,049,792, Elsnau, issued Sep. 20, 1977;Canadian Patent 1,164,347, Beckmeyer et al., issued Mar. 27, 1984; U.S.Pat. No. 5,019,375, Tanner et al., issued May 28, 1991; and U.S. Pat.No. 5,429,816, Hofrichter et al., issued Jul. 4, 1995; whichdescriptions are incorporated herein by reference.

The antiperspirant gel-solid stick compositions of the present inventioncan also be formulated to comprise other dispersed solids or othermaterials in addition to or in place of the particulate antiperspirantactive. Such other dispersed solids or other materials include anymaterial known or otherwise suitable for topical application to humanskin. The antiperspirant gel-solid stick compositions can also beformulated as gel-solid stick compositions which contain noantiperspirant or other active material, particulate or otherwise.

Method of Manufacture

The antiperspirant gel-solid stick compositions of the present inventionmay be prepared by any known or otherwise effective technique, suitablefor providing an antiperspirant gel-solid stick composition having therequisite crystalline matrix and other product characteristics describedherein. Such methods involve formulation of the essential components ofthe composition to form a gel-solid having the requisite elastic toviscous moduli ratio, product hardness, and visible residue index,wherein the crystalline matrix within the composition compriseselongated non-polymeric gellant crystals having an aspect ratio ofgreater than about 2, preferably greater than about 6, and an averageparticle diameter that is minimized (preferably to less than about 1 μm)through techniques directed to minimizing crystalline particle size in acomposition.

Crystalline particle size in the preferred embodiments of the presentinvention can be determined by techniques well known in the art, whichincludes light or electron microscopy of the composition, wherein thecomposition is formulated for analysis purposes without particulateantiperspirant active or other solid particulates. Without suchreformulation, it is more difficult to directly determine anddistinguish crystalline gellant particle size and morphology from theparticle size and morphology contributed from other non-gellantparticulates. The reformulated composition is then evaluated by light orelectron microscopy or other similar method.

Techniques for preparing the antiperspirant gel-solid stick compositionsof the present invention include those methods suitable for formulatingcompositions containing small gellant crystalline particles. Suitabletechniques for minimizing crystalline gellant particle size include theuse of nucleating agents, formulation with select carriers or gellantsor carrier/gellant combinations, controlling rates of crystallizationincluding controlling formulation, controlling process flow rate, andprocessing temperatures, and other methods described herein. All suchmethods should be applied to the formulation to control or minimizegellant crystal particle size, and/or to form the desired elongatedcrystalline particles, to thus form the desired crystalline matrix ofthe composition.

Method of Use

The antiperspirant gel-solid stick compositions may be applied topicallyto the axilla or other area of the skin in an amount effective to treator reduce perspiration wetness and malodor. The composition ispreferably applied in an amount ranging from about 0.1 gram to about 20grams, more preferably from about 0.1 gram to about 10 grams, even morepreferably from about 0.1 gram to about 1 gram, to the desired area ofthe skin. The compositions are preferably applied to the axilla or otherarea of the skin, one or two times daily, preferably once daily, toachieve effective antiperspirant and malodor control over an extendedperiod.

EXAMPLES

The following non-limiting examples illustrate specific embodiments ofthe antiperspirant gel-solid stick compositions of the presentinvention, including methods of manufacture and use.

Each of the exemplified compositions are prepared by combining all ofthe listed components except the antiperspirant active and othermaterials such as perfumes. The combined components are heated to about100° C. with agitation to form a hot liquid, after which all othermaterials are added to the heated liquid. The heated liquid is allowedto cool with agitation until just before the point of solidification, atwhich point the cooled, liquid composition is filled into applicatorpackages and allowed to cool and solidify to the requisite producthardness.

Each of the exemplified compositions comprise a crystalline gel matrixcontaining crystalline particles having an aspect ratio of greater thanabout 6, and an average crystalline gellant particle size of less thanabout 1 μm. Each of the exemplified compositions also have a visibleresidue index of between about 11 and about 30 L-value, a producthardness of between about 500 and 5,000 gram·force, and a G'/G" ratio ofbetween about 0.1 and about 100. Each of the exemplified antiperspirantcompositions are applied topically to the axilla area of the skin, inaccordance with the methods of use described herein, and provideimproved low residue performance, efficacy and aesthetics.

    ______________________________________                                                  Examples 1-6                                                        Component   No. 1   No. 2   No. 3                                                                              No. 4                                                                              No. 5 No. 6                             ______________________________________                                        D5 Cyclomethicone.sup.1                                                                   15      19.5    45   40   60    47.8                              12-Hydroxystearic                                                                         7.0     3.5     7.0  7.0  8.0   7                                 acid                                                                          2-Dodecyl-N,N'-                                                                           2       1       2    2    --    --                                dibutylsuccinamide                                                            Polyether siloxane.sup.2                                                                  --      --      --   --   5.0   --                                Dimethicone copolyol.sup.3                                                                50      50      --   --   --    --                                Dimethyl-diphenyl-                                                                        --      --      20   --   --    --                                siloxane.sup.4                                                                Silicone polyether                                                                        --      --      --   25   --    --                                copolymer.sup.5                                                               Sucrose polyester.sup.6                                                                   --      --      --   --   1.0   --                                Octodocecanol                                                                             --      --      --   --   --    14                                Dimethicone copolyol.sup.7                                                                --      --      --   --   --    2                                 Disodium EDTA                                                                             --      --      --   --   --    0.2                               C20-C40 Alcohol.sup.8                                                                     --      --      --   --   --    0.5                               C20-C40 Pareth 10.sup.9                                                                   --      --      --   --   --    1.25                              C20-C40 Pareth 40.sup.10                                                                  --      --      --   --   --    1.25                              Al Zr trichloro-                                                                          26      26      26   26   26    26                                hydrex glyc                                                                   Residue (L-Value)                                                                         23.5    24      23   21   29                                      Hardness (gram-Force)                                                                     2300    1200    850  750  1230                                    G'\G"                                                                           15      10      10   5    10                                      ______________________________________                                         .sup.1 Dow Corning 245 Fluid; General Electric SF1202                         .sup.2 EM97 from Goldschmidt                                                  .sup.3 DC3225C from Dow Corning                                               .sup.4 SF1023 from G.E. Silicones                                             .sup.5 SF1188a from G.E. Silicones                                            .sup.6 Sucrose octaester esterified predominately with behenic acid           moieties                                                                      .sup.7 DC1401 from Dow Corning                                                .sup.8 Unilin 425 from Petrolite                                              .sup.9 Unithox 450 from Petrolite                                             .sup.10 Unithox 480 from petrolite                                       

What is claimed is:
 1. An anhydrous antiperspirant gel-solid stickcomposition comprising:(a) from about 0.5% to about 60% by weight ofparticulate antiperspirant active; (b) from about 1% to about 15% byweight of a solid non-polymeric gellant that is substantially free oforganic polymeric gellants, dibenzylidene alditol, inorganic thickeningagents, derivatives of n-acyl amino acid, or combinations thereof; (c)from about 10% to about 80% by weight of an anhydrous liquid carriercontaining a silicone liquid carrier selected from the group consistingof polyalkylsiloxanes, polyalkyarylsiloxanes, polyestersiloxanes,polyethersiloxane copolymers, polyfluorosiloxanes, polyaminosiloxanes,and combinations thereof; andwherein the composition has a visibleresidue index of from about 11 to about 30 L-value, a product hardnessof from about 500 gram·force to about 5,000 gram·force, and a ratio ofan elastic to viscous moduli of from about 0.1 to about
 100. 2. Thecomposition of claim 1 wherein the composition contains from about 0.1%to about 50% by weight of the silicone carrier.
 3. The composition ofclaim 2 wherein the composition contains from about 1% to about 10% byweight of the silicone carrier.
 4. The composition of claim 2 whereinthe silicone carrier is selected from the group consisting ofdimethicone copolyol, tetraethoxysilane, tetramethoxysilane,hexamethoxysilicone, oxmethoxytrisiloxane, phenyl trimethicone,tetramethyl-tetraphenyl-trisiloxane; laurylmethicone copolyol cetyldimethicone, stearyl dimethicone, caproyl trimethicone,stearoxytrimethylsilane dimethiconal, dimethiconol,stearoxytrimethylsilane, trimethylsilylamodimethicone,trimethylsilylamodimethicone, trimethylsiloxysilicate,dimethyl-diphenyl-siloxane, methylphenyl siloxane, methylphenylsiloxane, hexamethyl-3-phenyl-3- trimethylsilyl!oxy!trisiloxane,trimethylsiloxysilicate, stearoxy dimethicone, tetrabutoxypropyltrisiloxane, bis-phenylhexamethicone tris tributoxysiloxy!methylsilane,and combinations thereof.
 5. The composition of claim 2 wherein thesolid non-polymeric gellant is selected from the group consisting of12-hydroxystearic acid, esters of 12-hydroxystearic acid, amides of12-hydroxystearic acid, and combinations thereof.
 6. The composition ofclaim 5 wherein the solid non-polymeric gellant is selected from thegroup consisting of 12-hydroxystearic acid, 12-hydroxystearic acidmethyl ester, 12-hydroxystearic acid ethyl ester, 12-hydroxystearic acidstearyl ester, 12-hydroxystearic acid benzyl ester, 12-hydroxystearicacid amide, isopropyl amide of 12-hydroxystearic acid, butyl amide of12-hydroxystearic acid, benzyl amide of 12-hydroxystearic acid, phenylamide of 12-hydroxystearic acid, t-butyl amide of 12-hydroxystearicacid, cyclohexyl amide of 12-hydroxystearic acid, 1-adamantyl amide of12-hydroxystearic acid, 2-adamantyl amide of 12-hydroxystearic acid,diisopropyl amide of 12-hydroxystearic acid, and combinations thereof.7. The composition of claim 6 wherein the solid non-polymeric gellant is12-hydroxystearic acid.
 8. The composition of claim 2 wherein the solidnon-polymeric gellent comprises a gellant conforming to the formula:##STR5## wherein a) R₁ is nil, hydroxy, hydrogen, aryl, siloxane orsaturated or unsaturated, substituted or unsubstituted, straight,branched or cyclic chain C₁ -C₂₂ alkyl, C₁ -C₂₂ alkenyl, C₁ -C₂₂ alkoxy,C₁ -C₂₂ alkyl esters, C₁ -C₂₂ alkyl ethers, or C₁ -C₂₂ alkyl substitutedaryl;b) R₂, R₄, R₅ and R₆ are independently or together, hydrogen,hydroxy, aryl, siloxane or saturated or unsaturated, substituted orunsubstituted, straight, branched or cyclic chain C₁ -C₂₂ alkyl, C₁ -C₂₂alkenyl, C₁ -C₂₂ alkoxy, C₁ -C₂₂ alkyl esters, C₁ -C₂₂ alkyl ethers, orC₁ -C₂₂ alkyl substituted aryl; c) R₃ is nil, hydroxy, hydrogen,saturated or unsaturated, substituted or unsubstituted, straight,branched or cyclic chain C₁ -C₄ alkyl, C₁ -C₄ alkenyl, C₁ -C₄ alkoxy, C₁-C₄ alkyl esters or C₁ -C₄ alkyl ethers; d) R₇ and R₈ are independentlyor together, nil, hydrogen, hydroxy, aryl, siloxane or saturated orunsaturated, substituted or unsubstituted, straight, branched or cyclicchain C₁ -C₂₂ alkyl, C₁ -C₂₂ alkenyl, C₁ -C₂₂ alkoxy, C₁ -C₂₂ alkylesters, C₁ -C₂₂ alkyl ethers, or C₁ -C₂₂ alkyl substituted aryl; e) R₉is nil or hydrogen; f) R₁₀ and R₁₁ are independently or together, nil,hydrogen, hydroxy, aryl, siloxane or saturated or unsaturated,substituted or unsubstituted, straight, branched or cyclic chain C₁ -C₆alkyl, C₁ -C₆ alkenyl, C₁ -C₆ alkoxy, C₁ -C₆ alkyl esters, C₁ -C₆ alkylethers, or C₁ -C₆ alkyl substituted aryl; g) X is nil, nitrogen, aryl or.paren open-st.CH₂ .paren close-st._(n) where n is an integer from 1 to6; h) Y is nil, acyl or carbonyl; i) Z is nil, hydrogen, hydroxy, aryl,siloxane, nitrogen or saturated or unsaturated, substituted orunsubstituted, straight, branched or cyclic chain C₁ -C₂₂ alkyl, C₁ -C₂₂alkenyl, C₁ -C₂₂ alkoxy, C₁ -C₂₂ alkyl esters, C₁ -C₂₂ alkyl ethers, orC₁ -C₂₂ alkyl substituted aryl; and j) "a" is a double or single bond,provided:(i) when X is nil, Y, Z, R₃, R₇ and R₈ are nil, C' is bondeddirectly to C" and R₁ is not a hydrogen; (ii) when X and Z are not niland Y is nil, X is directly bonded to Z; (iii) when Z is nil, a hydrogenor a hydroxy, R₇ and R₈ are nil; and (iv) when "a" is a double bond, R₃and R₉ are nil.
 9. The composition of claim 5 wherein the solidnon-polymeric gellant are elongated crystalline particles having anaspect ratio of at least about
 2. 10. The composition of claim 9 whereinthe solid non-polymeric gellant are elongated crystalline particleshaving an aspect ratio of at least about
 6. 11. The composition of claim5 herein the solid non-polymeric gellant are crystalline particleshaving an average particle size of less than about 1 μm.
 12. Thecomposition of claim 11 wherein the composition has a DifferentialScanning Calorimeter onset temperature of from about 25° C. to about 85°C.
 13. The composition of claim 12 wherein the composition has aDifferential Scanning Calorimeter onset temperature of from about 30° C.to about 60° C.
 14. The composition of claim 11 wherein the solidnon-polymeric gellant are crystalline particles having an averageparticle size of less than about 0.2 μm.
 15. The composition of claim 5wherein the composition has a product hardness of from about 750gram·force to about 2,000 gram·force.
 16. The composition of claim 15wherein the composition has a ratio of an elastic to viscous moduli offrom about 0.1 to about
 50. 17. The composition of claim 5 wherein thecomposition further comprises a volatile silicone carrier liquid carrierwhich conforms to the formula: ##STR6## wherein n is from about 3 toabout
 7. 18. The composition of claim 17 wherein the anhydrous liquidcarrier further comprises a non-volatile silicone liquid carrier havinga viscosity of less than about 100,000 centistokes.
 19. The compositionof claim 5 wherein the composition is substantially free of solid fattyalcohols having from 12 to 40 carbon atoms.
 20. The composition of claim5 wherein the particulate antiperspirant active has an average particlesize of from about 20 μm to about 100 μm.
 21. The composition of claim 5wherein the particulate antiperspirant active has an average particlesize of less than about 2 μm.
 22. A method for treating or reducingperspiration wetness and malodor, comprising applying from about 0.1gram to about 20 grams of the composition of claim 1 to the desired areaof the skin.
 23. A method for treating or reducing perspiration wetnessand malodor, comprising applying from about 0.1 gram to about 20 gramsof the composition of claim 7 to the desired area of the skin.
 24. Amethod for treating or reducing perspiration wetness and malodor,comprising applying from about 0.1 gram to about 20 grams of thecomposition of claim 11 to the desired area of the skin.
 25. A methodfor treating or reducing perspiration wetness and malodor, comprisingapplying from about 0.1 gram to about 20 grams of the composition ofclaim 17 to the desired area of the skin.